1. Field of the Invention
The present invention relates to reinforced laminar flow control (LFC) structures used in aerospace applications, and more particularly to threaded fasteners used to secure truss core LFC panel structures to underlying aircraft substructures, such that the head of each fastener lies flush with, and seals the opening in the outer surface of the LFC panel structure through which the fastener has been inserted, while a load-bearing portion adjacent the fastener threads functions to secure the panel structure to the underlying substructure.
2. Background of the Invention
Recently, designers of aerospace vehicles developed skin or panel structures which have facilitate conformance of moving air or other fluid to the surface over which it flows. Such structures, known as laminar flow control (LFC) structures, in recent years have taken the form of reinforced truss core panel members. These panel members must be secured to underlying airframe substructures via suitably chosen fastening systems.
One of the most critical difficulties in securing these structures to the airframe is in maintaining the precision of fit of the secured parts. Often manufacturing tolerances of the panel structures as well as the fastening mechanisms present the greatest obstacles in achieving the desired precision. To overcome this problem, fastening systems of various forms have been tried, from simple fasteners, such as rivets or bolts, to more complex devices, such as intricate latching mechanisms. Still, precision of fit remains a problem.
Moreover, the key objective of today's aerospace industry is to achieve optimum laminar flow. Thus, flow contacting surfaces of fastened panels, as well as of the fasteners securing the panels must present surfaces which act to minimize turbulence of the moving fluid. To date, no known system achieves these objectives.